Summary

When a user runs hermes setup or hermes model while the gateway is running (e.g. on Home Assistant, Telegram, Discord), there's a race condition that can cause the gateway to send requests with an incompatible model name to the new provider.

Root Cause

_update_config_for_provider() in hermes_cli/auth.py (line ~1544) writes the new provider and base_url to config.yaml immediately — before model selection happens.

In the MiniMax setup flow (setup.py lines 1036-1037):

_update_config_for_provider("minimax", pconfig.inference_base_url)  # writes to disk NOW
_set_model_provider(config, "minimax", pconfig.inference_base_url)
# ... model selection happens much later at line ~1278

Since the gateway re-reads config.yaml per-message, this creates a window where:

• model.provider = minimax, model.base_url = https://api.minimax.io/v1
• model.default = anthropic/claude-opus-4.6 (unchanged from previous provider)

The gateway then sends anthropic/claude-opus-4.6 to MiniMax's API, which doesn't serve that model.

Reproduction

1. Configure OpenRouter with anthropic/claude-opus-4.6 (default)
2. Start the gateway (hermes gateway run)
3. Chat via Home Assistant / Telegram — works fine
4. In a separate terminal, run hermes setup or hermes model
5. Select MiniMax as provider, enter API key
6. Before completing model selection, send a message via the gateway
7. The gateway picks up MiniMax as provider but still uses the Claude model name → fails

Even without the race: if the user selects "Keep current" at the model selection step, the model stays as anthropic/claude-opus-4.6 permanently — which is always wrong for non-OpenRouter providers.

Affected Providers

Any non-OpenRouter provider where the model name format differs: MiniMax, MiniMax-CN, Z.AI, Kimi, Anthropic (native). The OpenRouter-formatted model name (anthropic/claude-opus-4.6) won't work on these endpoints.

Suggested Fixes

Option A (minimal): Don't write config.yaml until the full setup flow completes. Buffer provider + base_url changes in memory, only flush to disk after model selection.

Option B (defensive): When _update_config_for_provider changes the provider, also set model.default to the first model in that provider's default list (e.g. MiniMax-M2.5 for minimax). The user can still change it during model selection, but at least the intermediate state is valid.

Option C (validation): Add a gateway-side sanity check: if the resolved provider is not openrouter and the model name contains a / prefix (OpenRouter format), log a warning and refuse to start the agent until the config is fixed.

User Report

Reported by a Discord user (Hunter) running Hermes on Home Assistant. His session log showed model: anthropic/claude-opus-4.6 with base_url: https://api.minimax.io/v1 — the agent appeared to "switch providers mid-conversation" from his perspective.